This invention relates to a power transmission system for a snowmobile and more particularly to an improved arrangement for driving the driving belt of a snowmobile.
It is conventional in snowmobile construction to mount the driving internal combustion engine so that its output shaft rotates about an axis that extends transversely to the longitudinal center line of the snowmobile. The engine output shaft is then coupled through a variable transmission, which may include a centrifugal clutch, to the drive belt. Due to the substantial width of the drive belts of the snowmobile, it has heretofore, been the practice to drive the variable transmission off one end of the engine output shaft. However, this has several disadvantages.
In the first instance, if the engine output shaft also drives the variable transmission, side loadings on the engine output shaft will be generated due to the inherent operation of the variable transmission. This can place undue wear on the engine output shaft.
In addition, when the variable transmission and a centrifugal clutch is placed on the end of the engine output shaft, then the overall drive package becomes quite large. This is a particular problem when a multiple cylinder engine is employed since the engine itself may be quite long. In addition, driving the transmission off one end of the engine output shaft, even if the transmission is driven through an intermediate shaft, can put substantial torsional loading on the output shaft of the engine.
It is, therefore, a principal object of this invention to provide an improved power transmission system for a snowmobile.
It is a further object of this invention to provide a power transmission system for a snowmobile wherein the engine and transmission package may be kept quite compact even when multiple cylinder engines are employed.
It is a further object of the invention to provide an improved arrangement for driving an intermediate shaft which drives a variable transmission for a snowmobile drive from an engine without placing large torsional stresses on the engine output shaft.